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From: Krishna Chaitanya <chaitanya.mgit@gmail.com>
To: Johannes Berg <johannes@sipsolutions.net>
Cc: Guy Harris <guy@alum.mit.edu>,
	"radiotap@netbsd.org" <radiotap@netbsd.org>,
	Simon Barber <simon@superduper.net>,
	Richard Sharpe <realrichardsharpe@gmail.com>,
	linux-wireless <linux-wireless@vger.kernel.org>,
	Maya Erez <merez@codeaurora.org>,
	wil6210@qti.qualcomm.com
Subject: Re: Correct radiotap header for 802.11ad
Date: Wed, 11 Dec 2019 18:50:46 +0530
Message-ID: <CABPxzY+BCcjFvQtPPdeBBOY1zcXzVd23GsSPKbd5BRsKRsTeog@mail.gmail.com> (raw)
In-Reply-To: <8f7c0c22c9732cc831686df4b93dedf37e72d219.camel@sipsolutions.net>

On Wed, Dec 11, 2019 at 6:28 PM Johannes Berg <johannes@sipsolutions.net> wrote:
>
> On Wed, 2019-12-11 at 15:09 +0530, Krishna Chaitanya wrote:
> >
> > > For both the Linux userspace reporting and radiotap then, this
> > > completely ignores the existence of the MCSes 9.1 and 12.1-12.6, which
> > > cannot be captured in either format right now. Maybe the extended SC
> > > MCSes are just not used by equipment in the field?
> > >
> > They are used. Unfortunately, Linux-wireless doesn't have native support for DMG
> > wil6210 and our driver has to workaround by using HT IE's
> > (ieee80211_supported_band).
>
> You make it sound like that some sort of thing that Linux cannot really
> do better. That's far from the truth! We keep extending this (HT, VHT,
> HE recently) and there's no fundamental reason we couldn't do extensions
> for DMG. It's just that nobody who actually has a driver for Linux
> bothered doing so!
Sorry, that wasn't my intent, as there is a single upstream driver I guess
it was easier to workaround than to properly add support. I agree that
it shouldn't
be hard, may be we can do it properly for 11ay.
> > > In any case, to capture DMG properly I'd say we need a new radiotap
> > > field with at least
> > >  * (base) MCS
> > >  * Extended SC MCS bit
> > > and it should probably optionally cover the other possible fields as
> > > well
> > >  * Scrambler Initialization
> > >  * Length (?)
> > >  * Additional PPDU bit
> > >  * PPDU type bit
> > >  * Training Length
> > >  * Beam Tracking Request
> > >  * Last RSSI
> > >  * Turnaround
> > yes, we definitely need this, there are some additional fields in
> > 11ay, but I guess that
> > discussion is for another time.
>
> Somebody (@QCA I guess, I don't have any functioning driver/hardware for
> Linux for this) really should sit down and define the extensions to
> cfg80211/nl80211 to capture the data properly, and a radiotap extension.
> None of that is hard, I've done it for VHT before and HE recently.



  reply index

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-08-22 19:41 Richard Sharpe
     [not found] ` <CACyXjPzq-ePB1ux6wi_Rv3onPKXomcJcm15XJwA51u0E4W2txw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-08-22 20:59   ` Guy Harris
     [not found]     ` <38F46E1D-1C4A-48DC-A906-9522006E8474-FrUbXkNCsVf2fBVCVOL8/A@public.gmane.org>
2015-08-22 22:06       ` Richard Sharpe
     [not found]         ` <CACyXjPx81fh_jeQSUjE-_w8NQ_Jr-ajmnVWSopfzcLPOWoGmGg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-08-22 22:24           ` Guy Harris
2015-08-22 23:34       ` Guy Harris
     [not found]         ` <1606812C-649C-4C06-ABE0-AE2F4474BCD0-FrUbXkNCsVf2fBVCVOL8/A@public.gmane.org>
2015-08-24  7:40           ` Johannes Berg
     [not found]             ` <1440402013.3735.1.camel-cdvu00un1VgdHxzADdlk8Q@public.gmane.org>
2015-08-24 16:21               ` Richard Sharpe
     [not found]                 ` <CACyXjPwSZPV+U_=zQpDBpeBnhMntzEFhyJnBOw3-N8qPfyHc1A-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-08-24 16:28                   ` Johannes Berg
2015-08-26 22:59                   ` Simon Barber
     [not found]                     ` <55DE44EB.6080603-vp0mx6+5gkqFX2APIN6yfw@public.gmane.org>
2015-08-27  1:17                       ` Guy Harris
     [not found]                         ` <126B842D-05EA-4510-BC9B-DB1A4AABEC12-FrUbXkNCsVf2fBVCVOL8/A@public.gmane.org>
2015-09-10 18:25                           ` Guy Harris
     [not found]                             ` <1135A126-6A5A-4C84-A52D-13C0387609CC-FrUbXkNCsVf2fBVCVOL8/A@public.gmane.org>
2015-09-17 16:37                               ` Johannes Berg
2019-12-10 23:51                                 ` Guy Harris
2019-12-11  8:32                                   ` Johannes Berg
2019-12-11  9:39                                     ` Krishna Chaitanya
2019-12-11 12:57                                       ` Johannes Berg
2019-12-11 13:20                                         ` Krishna Chaitanya [this message]
2019-12-20 21:56                                     ` Guy Harris
2015-09-17 16:32                       ` Johannes Berg
2015-08-26 22:56       ` Simon Barber

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